Carillion, the outsourcing giant, has been accused of racial discrimination by Asian-origin hospital workers who claim they were told by white managers to give gold watches, bangles and cash in exchange for favours.

Forty eight staff of Goan origin said in employment tribunal papers that they were subjected to a culture of intimidation and fear by supervisors at the Great Western Hospital in Swindon, Wiltshire.

One particularly disturbing aspect of this, it is alleged, was the practice of managers to demand "gifts" from non-white staff including cash, jewellery, cigarettes, alcohol and, in one instance, a duvet.

In return, staff would be granted holiday and overtime requests, allowing them to return to Goa to visit family members or attend religious festivals, it is claimed.

When staff complained of the practice as early as 2007, they faced harassment for trade union membership and whistle-blowing, it is claimed.

A spokeswoman for Carillion said that there were incidents of gift giving for favours from managers, but added that these have been investigated thoroughly and disciplinary procedures are in place. The company will vigorously defend itself against the claims.

Carillion is one of the UK's leading companies in providing support services to local and central government through a variety of Public and Private Partnership projects. In a 2012 interim report, entitled 'Making Tomorrow a Better Place', the company's revenue is listed as £2.2bn with underlying profit before taxation amounting to £73.1m.

Jose Estrocio, a claimant and GMB union representative, said that the tribunal cases follow years of intimidation and complaints.

"We are in a developed country and had to give money and gold for holidays. None of the white cleaners had to do this, it was only the Goan community."

Shah Qureshi, a partner at the law firm Bindmans, said that those that complained were victimised with the threat of disciplinary action.

"This type of scenario is akin to the 'master and servant' relationship of Victorian Britain and should have no place in the 21st Century," he said.

Most of the workers were recruited in Britain to work for Carillion as porters, cleaners, and members of the housekeeping staff in Swindon's biggest hospital.

Supervisors maintained a system whereby they expected gifts in return for favours but their demands were only made of non-white employees, according to the writ.

Paulo Fernandes, a union rep, claimed that when he applied for a porter's job, he was asked by a female manager "What will you give me?" before being asked for a gold chain of a certain length, saying it had to be visible and not too long or too short.

Fernandes, accompanied by a friend, handed over a chain belonging to his wife at the manager's house, it is claimed.

He began work as a porter, but after four weeks was told that he was not doing his job properly and would have to return to a housekeeping job, it is also claimed. "The claimant started to cry and was in complete shock," the papers noted.

Another claimant, Irene de Souza, wanted to travel to Goa for 10 days in January 2011.

She claimed a manager asked her for a gift, and she felt compelled to hand over perfume and a watch worth £25. This was particularly distressing, she claimed, because it was a gift from her children.

The gift-giving system carried on for years before the claimants joined the GMB union and issued a collective grievance procedure in December 2011, court papers said.

The company carried out an investigation, the papers said, and the claimant cleaners were interviewed and told that their evidence was confidential.

However, in June, the company told the workers that they were going to be subject to a disciplinary hearing because they had given gifts in return for benefits, the papers alleged.

Staff say that one of the managers involved in obtaining gifts has left the company.

A spokeswoman for Carillion said they have investigated the allegations and concluded that gifts have been given in exchange for favours from managers.

So far, 58 members of staff have filed claims with the tribunal since February, she said, and these will be "vigorously" defended by the company.

"In the circumstances it was appropriate that Carillion carried out disciplinary processes with employees who admitted giving or facilitating gifts for advantage. This is an ongoing process but outcomes so far have included training to those who gave gifts for advantage – not sanction.

"To be clear: Carillion will not tolerate racism or racist remarks from any of our employees, and racism goes completely against all our values as an organisation, as well as our policies.

"Claims are presently being subjected to a formal case management process by the tribunal. It is only once this process is completed at the end of this year that we will have a clear understanding of which cases the tribunal will expect Carillion to defend – and which claims the tribunal will not allow to proceed," she said.